Agricultural and construction vehicles typically employ hydraulic cylinders to power a variety of specialty implements that attach to the vehicles. For example, typical front-end loaders have a pair of arms that are raised and lowered by hydraulic cylinders, as well as implements attached to the arms that are operated by hydraulic cylinders. Some exemplary front end loaders using hydraulic lines to power hydraulic cylinders are described by U.S. Pat. No. 3,512,665 to Westendorf; U.S. Pat. No. 4,085,856 to Westendorf; U.S. Pat. No. 4,787,811 to Langenfeld et al.; U.S. Pat. No. 4,051,962 to Westendorf; U.S. Pat. No. 4,606,692 to Langenfeld et al.; and U.S. Pat. No. 4,930,974 to Langenfeld et al., all incorporated herein by reference.
Hydraulic lines are required to deliver hydraulic fluid to hydraulic cylinders. Additionally, two way cylinders must be connected to hydraulic lines at two ports typically located on opposite ends of the cylinders. In order to provide hydraulic fluid to most commonly available cylinders, at least one hydraulic line is usually strung along the cylinder to connect near the rod end of the cylinder. Thus, loaders that have multiple two way cylinders to operate implements are typically required to have many (often unsightly) hydraulic lines strung along the arms of the loader as shown in FIGS. 1-4. Loaders with complex implements, such as pinching fingers, often have even more hydraulic lines.
It is known in the prior art, as shown in FIG. 1 from U.S. Pat. No. 4,050,596 and FIGS. 2-4, that hydraulic cylinders 10 and hydraulic lines 15 connected to lift arms 20 and implement attachments 25 are commonly located on portions of loaders 30 exposed to potentially rough environments. Hydraulic lines 15 are particularly susceptible to being snagged on objects since the lines must be relatively slack to allow for movement of the hydraulic cylinders. Hydraulic lines 15 connected to the lift arm 20 may also snag on or be pinched by the engine compartment 35 when the lift arms are raised and lowered.
The problem of developing a guard structure for hydraulic lines is further complicated by the flexible hydraulic conduits extending along the boom. The guard structure must not interfere with the movement of the hydraulic lines at key loader arm pivot points. The required movement of the cylinders relative to one another hinders development of a single satisfactory guard structure capable of protecting numerous hydraulic lines and cylinders of a front end loader.
In addition to being subject to snagging during operation, exposed hydraulic lines also often create an unrefined appearance for the vehicle, as shown in FIGS. 1-4 of the present application. Improvements to the appearance of hydraulic cylinders and lines have been proposed, such as those shown in U.S. Pat. No. D184,544 issued to Pessler, U.S. Pat. No. D194,362 issued to Prince, and U.S. Pat. No. D408,420 issued to Büter. Previous attempts to reduce the appearance of hydraulic lines have involved complicated and expensive methods such as the hydraulic cylinder with dual internal fluid conduits disclosed in U.S. Pats. No. 7,243,593 and 6,994,512 issued to Westendorf. Further improvements, however, in the appearance, cost, and function of devices that protect both hydraulic lines and hydraulic cylinders are desired.
There have been attempts to develop guards for hydraulic lines and cylinders such as those disclosed by U.S. Pat. Nos. 4,265,063 and 4,267,674 issued to Muller. However, these guards disclosed by Muller do not completely surround the hydraulic cylinders and lines. Additionally, the Muller guards do not significantly immobilize portions of the hydraulic lines adjacent to the hydraulic cylinders. The Muller guards are also fabricated from heavy sheet metal, making them expensive to fabricate, install and replace, and therefore not readily adaptable for certain applications, especially on lighter duty vehicles.
Accordingly, an object of the present invention is to provide a guard structure that protects hydraulic cylinders and lines from damage.
Another object of the present invention is to provide a guard structure that is lightweight and easily replaceable.
A further object of the present invention is to provide a structure that does not interfere with the movement of a boom assembly.
Finally, an object of the present invention is to provide a guard structure that is economical to manufacture and refined in appearance.